The present invention is, in general, directed to laminated articles including filters and films. More specifically, the invention is directed to a laminated article, such as a filter, having a support scrim, a membrane, and an oleophobic enhancement agent disposed from an organic solvent onto the support scrim and membrane. The invention also concerns assemblies using the laminated articles.
Laminated articles have many uses, including, for example, as filters and films. The laminated articles can be formed with a variety of different properties which are often a result of the construction of the laminated articles. For example, appropriate materials and layers can be used in forming the laminated articles to provide the desired properties. Properties of the laminated articles can also be modified by treatments including, for example, chemical treatments. In a number of applications, laminated articles are useful as filters or protective films that allow the flow of air into or through the laminated article while preventing or restricting the flow of particulate matter, water, oil, other organic compounds, and/or other contaminants.
One example of a laminated article is a breather filter that permits the flow of a fluid, such as air, through the filter, but prevents or restricts the flow of particles and other contaminants (e.g., water and/or organic compounds). The filter typically includes one or more porous layers. The average pore size of the porous layer or layers of the filter influences the size of particles that can flow through the filter.
In addition, one or more layers of the filter may be treated with or formed using a material to prevent or resist the flow of selected compounds or contaminants through or into the layer. For example, a layer may be treated with or formed using a hydrophobic material to resist the passage of water through or into that layer. Conversely, the layer may be treated with or formed using a hydrophilic material. Other circumstances call for a layer or layers that are oleophobic or oleophilic.
In some circumstances, there is a need to prevent or restrict the flow of a variety of particles and fluids. For example, filters and films are often used in environments that are sensitive to contaminants with disparate properties, such as particulate matter, water, and oily materials. Such environments may include, for example, storage containers for oily materials and articles used near an engine. The disparate nature of the contaminants often requires the use of a combination of approaches to prevent or restrict the flow of these materials, including, for example, the choice of an appropriate average pore size, the choice of materials for the layers of the laminate article, and the treatment of one or more layers of the laminated article.
Generally, the present invention relates to laminated articles, methods of making the laminated articles, and assemblies using the laminated articles. One embodiment is an article having a treated laminate with an expanded polytetrafluoroethylene (PTFE) membrane and a porous support scrim. The treated laminate is formed by contacting a laminate having an expanded PTFE membrane and a porous support scrim with an oleophobic treatment agent dissolved in an organic solvent. The oleophobic treatment agent is deposited onto the expanded PTFE membrane and porous support scrim as the organic solvent is removed. A filter may be formed using the treated laminate.
Yet another embodiment is a method of making an article having an oleophobically-treated laminate. A laminate having an expanded PTFE membrane and a porous support scrim is brought into contact with an oleophobic treatment agent dissolved in an organic solvent. The oleophobic treatment agent is deposited onto the expanded PTFE membrane and porous support scrim as the organic solvent is removed.
A further embodiment is an assembly having a housing with a port to permit air flow into and out of the housing. A filter is disposed over the port to prevent or restrict the flow of contaminants. The filter includes a treated laminate with an expanded PTFE membrane and a porous support scrim. The treated laminate is formed by contacting a laminate having an expanded PTFE membrane and a porous support scrim with an oleophobic treatment agent dissolved in an organic solvent. The oleophobic treatment agent is then deposited onto the expanded PTFE membrane and porous support scrim as the organic solvent is removed.
One example of the assembly is a headlamp for a vehicle. The headlamp includes a light source and a housing around the light source. The housing has a port to permit air flow into and out of the housing with the filter having the treated laminate disposed over the port.
The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The Figures and the detailed description which follow more particularly exemplify these embodiments.